TUESDAY, Feb. 4, 2014 (HealthDay News) -- U.S. Food and Drug Administration approval of the Dexcom G4 Platinum Continuous Monitoring System has been expanded to include children with diabetes aged 2 years to 17 years, the agency said.

Previously approved for adults only, the device constantly monitors the user's blood sugar, checking for dangerously high or low levels, the FDA said in a news release. An estimated 25.8 million people in the United States -- including 215,000 under age 20 -- have diabetes.

The external device, known as a continuous glucose monitor, includes a small, narrow sensor that's inserted just under the skin. That combined with a blood glucose meter can help the user's doctor decide treatment options, such as the amount of insulin to prescribe, the FDA said.

The device was evaluated in clinical studies involving 176 people ages 2 to 17. The FDA warned the device's "performance in pediatric subjects was not as accurate as the performance of the same device in adults." Nonetheless, the agency said the device is still "effective for tracking and trending to determine patterns in glucose levels," and for warning users that their blood sugar had risen too high or fallen too low.